Fastpass hidden early next fetch times are a heavily guarded secret.
They come about when each ride has its own fastpass next fetch time depending on how busy that ride is. There is not enough space on the Fastpass to show a next fetch time for each and every ride.
They are used to let you get your fastpass for Lights, Motors and not have to wait two hours to get a fastpass for something else, and vice versa, to let you get your fastpass for Lights, Motors without waiting two hours from your previous fast pass.
Last year I noticed that Jungle Cruise had one. It was not a case of the fastpass machines being off line because the next fetch time on my Jungle Cruise fastpass was the exact same to the minute next fetch time on my Space Mountain fast pass.
Numbers hypothetical because I forgot the exact numbers: At 10 AM I got a Space Mountain fast pass with return time 2 PM and next fast pass at the worst case 12:05. At 11 AM I tried to get a fast pass at Jungle Cruise and succeeded, the return time was 11:45 and the next fetch time was 12:05, not 5 minutes after its maturity which would be 11:50.
I suppose that some day rides will be designated A or B* depending on popularity, the letter could change during the day. Fastpasses will show different next fetch times for A or B rides. If you get a fast pass, the come back time for you is cast in stone by being printed on the fast pass, even if the letter on the ride changes.
* or maybe, to repeat history, have five designations A through E.
